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fe4da5cc | 1 | * |
2 | * $Id$ | |
3 | * | |
4 | * $Log$ | |
5 | * Revision 1.1.1.1 1995/10/24 10:20:51 cernlib | |
6 | * Geant | |
7 | * | |
8 | * | |
9 | #include "geant321/pilot.h" | |
10 | *CMZ : 3.21/02 29/03/94 15.41.29 by S.Giani | |
11 | *-- Author : | |
12 | SUBROUTINE GNBOX (X, PAR, IACT, SNEXT, SNXT, SAFE) | |
13 | C. | |
14 | C. ****************************************************************** | |
15 | C. * * | |
16 | C. * COMPUTE DISTANCE UP TO INTERSECTION WITH 'BOX' VOLUME, * | |
17 | C. * FROM INSIDE POINT X(1-3) ALONG DIRECTION X(4-6) * | |
18 | C. * * | |
19 | C. * PAR (input) : volume parameters * | |
20 | C. * IACT (input) : action flag * | |
21 | C. * = 0 Compute SAFE only * | |
22 | C. * = 1 Compute SAFE, and SNXT only if SNEXT .GT.new SAFE * | |
23 | C. * = 2 Compute both SAFE and SNXT * | |
24 | C. * = 3 Compute SNXT only * | |
25 | C. * SNEXT (input) : see IACT = 1 * | |
26 | C. * SNXT (output) : distance to volume boundary * | |
27 | C. * SAFE (output) : shortest distance to any boundary * | |
28 | C. * * | |
29 | C. * ==>Called by : GNEXT, GTNEXT * | |
30 | C. * Authors R.Brun, P. Weidhaas ********* * | |
31 | C. * * | |
32 | C. ****************************************************************** | |
33 | C. | |
34 | #include "geant321/gconsp.inc" | |
35 | DIMENSION X(6), PAR(6) | |
36 | C. | |
37 | C. ------------------------------------------------------------------ | |
38 | C. | |
39 | SNXT = BIG | |
40 | S1 = BIG | |
41 | S2 = BIG | |
42 | S3 = BIG | |
43 | SAFX1= PAR(1)-X(1) | |
44 | SAFX2= PAR(1)+X(1) | |
45 | SAFY1= PAR(2)-X(2) | |
46 | SAFY2= PAR(2)+X(2) | |
47 | SAFZ1= PAR(3)-X(3) | |
48 | SAFZ2= PAR(3)+X(3) | |
49 | ||
50 | IF (IACT .LT. 3) THEN | |
51 | ||
52 | C ------------------------------------------------- | |
53 | C | Compute safety-distance 'SAFE' (P.Weidhaas) | | |
54 | C ------------------------------------------------- | |
55 | ||
56 | SAFE = MIN(SAFX1,SAFX2, SAFY1,SAFY2, SAFZ1,SAFZ2) | |
57 | ||
58 | IF (IACT .EQ. 0) GO TO 999 | |
59 | IF (IACT .EQ. 1) THEN | |
60 | IF (SNEXT .LT. SAFE) GO TO 999 | |
61 | ENDIF | |
62 | ENDIF | |
63 | ||
64 | ||
65 | C ------------------------------------------------ | |
66 | C | Compute vector-distance 'SNXT' (McPherson) | | |
67 | C ------------------------------------------------ | |
68 | ||
69 | IF(X(4).GT.0.) S1 = SAFX1/X(4) | |
70 | IF(X(4).LT.0.) S1 =-SAFX2/X(4) | |
71 | IF(X(5).GT.0.) S2 = SAFY1/X(5) | |
72 | IF(X(5).LT.0.) S2 =-SAFY2/X(5) | |
73 | IF(X(6).GT.0.) S3 = SAFZ1/X(6) | |
74 | IF(X(6).LT.0.) S3 =-SAFZ2/X(6) | |
75 | ||
76 | SNXT = MIN(S1,S2,S3) | |
77 | ||
78 | 999 CONTINUE | |
79 | END |